ThrowableProxy.getExtendedStackTraceAsString causes NullPointerException

I'm trying to write a poc with Log4j 2.1, where distributed processes are logging to a remote server. The server is currently running the bundled TcpSocketServer.createSerializedSocketServer with a custom layout plugin.

A process is logging an exception. I can then see in the custom layout plugin at the log server that the LogEvent doesn't contain a thrown, but that it contains a thrownProxy. So far so good. I'm then trying to get hold of a String representation of the message + stacktrace. I thought that I would be able to e.g invoke ThrowableProxy.getExtendedStackTraceAsString(), but that causes a NullPointerException since the throwable in the ThrowableProxy also is null after deserialization. Looks like ThrowableProxy assumes that throwable isn't null in a few methods.

The exception that is logged by the client process is a simple new Exception("A message");

The pom.xml that I'm using:

<dependency>
	<groupId>org.apache.logging.log4j</groupId>
	<artifactId>log4j-api</artifactId>
	<version>2.1</version>
</dependency>
<dependency>
	<groupId>org.apache.logging.log4j</groupId>
	<artifactId>log4j-core</artifactId>
	<version>2.1</version>
</dependency>
<dependency>
	<groupId>com.lmax</groupId>
	<artifactId>disruptor</artifactId>
	<version>3.3.0</version>
</dependency>

The stacktrace that I get in the server:

2014-12-05 14:30:44,601 ERROR An exception occurred processing Appender XXXXX java.lang.NullPointerException
	at org.apache.logging.log4j.core.impl.ThrowableProxy.getExtendedStackTraceAsString(ThrowableProxy.java:340)
	at org.apache.logging.log4j.core.impl.ThrowableProxy.getExtendedStackTraceAsString(ThrowableProxy.java:323)

Workaround:
To invoke ThrowableProxy. getExtendedStackTrace() and format the stacktrace + message with my own format methods.